Ah good, you recognized the next step about the drop downs.

I use SUBTOTALS and autofilters a lot for "one off" type situations. Once I want to repeatedly get the same information, I go to SUMIFS and COUNTIFS.

Pulling field yields should work well, but I see a challenge for farm and client yields. If you get the field sizes from your main log, then the acres will start multiplying by the number of loads. Getting the field size from a different table will work, but doing this before harvest is finished will mean your average yield per farm and client will look poor until then.

One other option is to use SUMIFS to get acres from your main log and then divide by the number of times that field showed up. Basically, do the same settings as the SUMIFS you use to get your field acres, but use COUNTIFS. That will get you your true acres with yield information that makes sense as each field is finished.

So your final formula will be something like this: (SUMIFS to get total bushels)/((SUMIFS for field acres)/(COUNTIFS for number of times the field showed up)).

I think I would break that up into at least two cells.